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Design Series I: Defining Spatial Expression - The Staircase

In the new Design series, Defining Spatial Expression, Prof. Ar. Rajini Itham Mahajan, Senior Architect, VBT Consortium and HOD, Aakar Academy of Architecture, Bengaluru discusses various elements that define Architecture in terms of their evolution, significance- aesthetic and functional and construction possibilities. In the first of the series, we will explore the unassuming yet versatile STAIRCASE.

The Staircase is defined as a series or a collective of steps as a construction element to connect different levels, with a supporting framework. The stair though essentially categorized as a connecting space for vertical movement also defines spatial order; it may be a sculpture, an accessory. The need for vertical urban growth in the modern times has further stressed the importance of the staircase. The staircase interactively responds to spaces around it in terms of a plan function. Modern day elevators and escalators may have replaced the staircase as a spatial element in semi public and public spaces. Nevertheless, the requirement for a stairwell and its location are critical, especially for safety with strict adherence to fire safety norms as per stipulated bye- laws.

Staircase in the design process
Image Credits: M/s. VBT Consortium

Evolution:

The first stairs may have been created accidentally, by pushing footholds into a slippery path, thus forming rough steps. In early civilizations, the ramp was also used to negotiate levels. Though this was advantageous in terms of ease of construction, it occupied too much space and was more slippery than horizontal ledges for ascending. Eventually, the Staircase evolved as a superior proposition for vertical movement.

However, after the Middle Ages, staircases gained a new interest, not only as a functional element, but also for embellishing Architecture. Stairways became symbolic of opulence and grandeur, gaining the status of the most significant spatial element, reflecting or sometimes even dictating a particular Architectural style.

Spatial and Visual Significance:

The staircase guides movement vertically and regulates alignment horizontally in the plan form, serving as a nodal junction. The staircase can also be exploited as a light well, especially in architecture sharing common walls or in compact sites. As a fire escape in multi storey, the staircase plays a pivotal role in PHE services and is a design determinant in urban architecture.

The staircase is one of the few architectural elements emphasizing the diagonal line. The Diagonal line links the vertical and the horizontal and conveys dynamic energy, emphasizing on movement. The stair shaft ensures visual connectivity across vertical volumes.

Apart from the primary function of connecting spaces at various levels, the staircase has found assorted uses in Architectural setting. Stairs are used as extended seating indoors or form Open air theatres outdoors. Limitations in space in urban settings have inspired designers to maximize space utilizations in residual spaces in the staircase for Storage solutions, display or even utility areas below, depending on head height.

Structural Sub Elements:

The width of the staircase varies depending on the private or public nature of space. Ranging from a minimum of 900 mm, grand staircases could boast a much greater width. The ideal width of staircase in a private building could be 1050 to 1200 mm. In Public buildings, 1500 mm could be the optimum width. Irrespective of the style and overall dimensions, most staircases consist of the following sub elements.

Tread: The tread is the horizontal part of the step upon which the foot is placed. This ranges from 250mm to 300 mm.

Riser: The riser is the vertical part of the step. In the earlier times, the tread was comparatively smaller than the riser, however, over time, this relationship changed. A broader tread and a lower riser catered to better ergonomics. The riser is ideally between 150mm to 170 mm. Empirical formulas, derived from anthropometric data, such as 1 Tread + 2 Risers = 600 to 650 mm have helped designers arrive at ideal staircase dimensions.

Staircase Components
Image Credits: M/s. VBT Consortium

Landing: The landing usually occurs at half the run of the staircase. This landing is a horizontal slab which may be for a pause in movement or for a change in direction. The landing itself could extend to form a deck, access mid landing spaces or become a habitable zone by itself in split level planning.

Handrail: The Handrail and the balustrade are a safety feature and support. The handrail is the dominantly visible part of the staircase and is placed at a height of 900 to 1050 mm from the step.

Classification
The staircase may be classified:

Based on Geometry: The staircase may be classified based on Geometry; as Dog legged, Open well, Spiral, L-shaped, Helical, Grand or Straight Flight. The Spiral and Dog legged staircases are the most compact in space planning and the Helical and the Grand staircase can be most dramatic.

Based on Material: Conventional staircases were made of brick, stone or wood, later with concrete or wrought iron. New age designs explore glass, steel, Fibre reinforced plastic and even recycled products.

Famous examples for staircases include the Spiral Staircase at the Vatican Museum, San Francisco's Tiled Steps and “Umschreibung" at KPMG Building, Munich among many others. Different dimensions of stairs have also been explored in Stepped wells of Gujarat and Rajasthan or perplexed visitors to the Wexner Art museum with a floating column over the staircase.

Be it for historical significance or religious connotation, the staircase has been a significant element in the built environment. Specifically during the Art nouveau, Contemporary and Post modern periods, the staircase has lent itself to be explored and reinvented by architects and designers.

Interestingly, the staircase has also intrigued the public with optical illusions like the Escher’s stairs or enthralled them with moving staircases in the popular Harry Potter series.

The staircase has influenced art and science of Architecture, necessitating a considerable amount of innovative thought and construction skill. Evolving from the primitive need to access higher levels due to terrain or for protection from natural forces, the staircase has emerged through Design history as one of the key determinants in the Architectural program. The staircase is indeed versatile.

Architecture is always known to reflect time, society, culture, thoughts and beliefs ...

Author

Rajini Itham Mahajan
I currently work in the capacity of Senior Architect with one of the oldest architectural practices practices in Bengaluru, M/s. VBT CONSORTIUM, specializing in large scale residential and commercial projects. I also teach at various schools of Architecture as a ... View full profile